Iodophors are physiologically acceptable complexes of iodine with certain organic polymers, as for example polyvinylpyrrolidone (povidone), in which the germicidal and microbicidal activity of the elemental iodine is maintained. In general, the useful iodophors are water soluble.
The organic polymers used to form an iodophor comprise a broad range in molecular weight and chain length, and may be either ionic or nonionic in character, as well as possessing either surfactant or non-surfactant properties. A loose bond forms between the iodine and organic polymer to form the complex or iodophor, and aqueous solutions of up to 30% by weight of iodine content may be prepared (all percents are by weight herein, except as otherwise noted).
The general class of organic iodophor compounds comprises two distinct polymer groups: povidone, and polydextrose, which are nondetergent, nonionic and nonsurface active polymers; and a broad variety of detergent/surface-active polymers including nonionic, anionic, and cationic surface active polymers. Both polymer groups are complexed with elemental iodine to form the iodophor. Anionic surface active agents are generally not capable of providing stable iodine complexes. However, certain anionic surface active agents, such as enumerated in U.S. Pat. No. 3,039,916, have been found to be suitable for forming iodine complexes for germicidal use. Povidone-iodine is the most effective and most widely used iodophor and for many years was substantially the only nondetergent, nonionic iodophor which has been found to be suitable for germicidal action in man and animals, has well as in environmental uses. The preparation of povidone iodine has been described in U.S. Pat. No. 2,739,922 and elsewhere.
Polydextrose iodine is a new nonionic, nonsurface active iodophor which has also been found to be highly effective, and the preparation and use thereof is described in U.S. Pat. No. 4,576,818.
The iodophors, and particularly povidone iodine and polydextrose iodine, are dispensed in various kinds of semisolid and liquid pharmaceutical preparations, such as solutions, ointments and aerosols. In the treatment of wounds, however, a powder formulation is desirable because of ease of application, namely simple sprinkling of the powder into and onto the wounds. For best results, such powder should be both homogeneous and free flowing.
However, the iodophors, and particularly the nonionic, nondetergent iodophors such as polydextrose iodine and povidone iodine, are amorphous, hygroscopic and nonfree flowing powders. They can be transformed into free flowing powders by the addition of glidants, such as talc. However, although talc is widely used as a dusting powder and is an innocuous substance when applied to the intact skin, it can induce severe granulomatous reactions when introduced into wounds or when applied during surgery. Consequently, powders of this type cannot be used for such purposes as the treatment of wounds.
Thus, there has been a need for developing a free flowing iodophor in powder form which does not contain a glidant such as talc and which can be applied to wounds and the like.